Submerged exhaust discharge for marine vessel

ABSTRACT

A marine exhaust system adapted for discharging marine exhaust below the water line through at least one streamlined conformal discharge fitting attached to the vessel hull. Each discharge fitting comprises a low profile body attached to the vessel hull in relation with an exhaust discharge conduit terminating in a thru-hull opening so as to discharge marine exhaust into the discharge fitting body. The discharge fitting preferably includes a forward end and an aft end connecting a main discharge fitting body disposed in spaced relation with the underside of the vessel hull. The discharge fitting body defines an exhaust outlet disposed on outboard side thereof so as to allow exhaust gas to exit in an outward and aft flow such that corrosive exhaust gas does not flow over the vessel propellers. Forward and aft baffles are disposed within the discharge fitting body to direct and re-direct exhaust gas flow. By maintaining a streamlined and low-profile/conformal shape, reduction in overall hull hydrodynamics due to increased drag is minimized.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of provisional U.S. Patent Application Ser. No. 61/088,106 filed on Aug. 12, 2008.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

N/A

COPYRIGHT NOTICE

A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or patent disclosure as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all rights whatsoever.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to exhaust systems and mufflers for use with internal combustion engines on marine vessels, and more particularly to an improved underwater exhaust discharge system that provides improved below-the-waterline exhaust discharge capability without significantly degrading the hydrodynamic performance of the vessel hull.

2. Description of Related Art

A marine vessel is typically configured with a propulsion system having an internal combustion engine mounted within the hull of the vessel. Exhaust generated by the engine is commonly combined with cooling water and ducted through an exhaust system to the stern or rear of the vessel via one or more exhaust pipes for discharge through one or more exhaust ports formed in the transom. Exhaust silencers (a/k/a “mufflers”) are often installed in the exhaust system to silence noise associated with the engine and exhaust gases. The propulsion and exhaust systems are primarily mounted within the hull. The hull generally comprises the shell and framework of the basis flotation oriented part of the vessel. The hull typically includes a bottom that slopes upward and outward (i.e. outboard) from the centerline or keel in the starboard and port directions eventually reaching the chine wherein a relatively sharp angle in the hull is formed. The chine generally identifies that part of the hull wherein the sides and bottom meet. The hull terminates forwardly in a bow and rearwardly at the steam.

A variety of structures are known in the background art for use in silencing marine exhaust noise. The present inventor has invented a number of novel marine exhaust components that have greatly improved the silencing and efficiency of marine exhaust systems. Among those inventions developed by a named inventor for the present invention are the following:

U.S. Pat. No. Entitled 4,918,917 Liquid Cooled Exhaust Flange 5,196,655 Muffler for Marine Engines 5,228,876 Marine Exhaust System Component Comprising a Heat Resistant Conduit 5,262,600 In-line Insertion Muffler for Marine Engines 5,444,196 In-line Insertion Muffler for Marine Engines 5,504,280 Muffler for Marine Engines 5,616,893 Reverse Entry Muffler With Surge Suppression Feature 5,625,173 Single Baffle Linear Muffler for Marine Engines 5,718,462 Muffler Tube Coupling With Reinforcing Inserts 5,740,670 Water Jacketed Exhaust Pipe for Marine Exhaust Systems 6,035,633 Water Jacketed Exhaust Pipe for Marine Exhaust Systems 6,564,901 Muffler for Marine Engine

The various marine mufflers and exhaust components made in accordance with the above-referenced patents have achieved tremendous success and widespread acceptance within the marine industry. Such muffler systems have been successfully installed on a wide variety of marine vessels having engines in excess of 1,000 horsepower.

One area ripe for advancement involves the discharge of marine exhaust from the vessel. Most marine exhaust systems are configured to discharge exhaust gas (and entrained cooling water) through discharge ports above the water line through outlets disposed at or near the transom. The background art, however, reveals a number of designs intended to discharge marine exhaust below the waterline. These designs are each burdened with complexities, inefficiencies, and limitations that have resulted in very limited success. For example, U.S. Pat. No. 4,509,927, issued to Ikeda, discloses a bottom exhaust for a high speed boat that requires fabrication of a hull with a grooved bottom. The Ikeda reference, however, requires complex hull fabrication. U.S. Pat. No. 5,078,631, issued to Harbert, discloses a marine exhaust system that discharges cooling water below the water line through a reverse scoop. Harbert merely discloses the discharge of cooling water below the water line. U.S. Pat. No. 5,505,644, issued to Ousley, II et al., discloses a system for discharging marine engine exhaust above the water line when at idle or low speeds, and below the surface of the water at high speed in a turbulent region generated by a hydrodynamic fitting fixed to the undersurface of the vessel hull. The Ousley reference, however, requires the use of hydrodynamic fitting which projects significantly from the bottom of the hull thereby degrading hydrodynamic efficiency of the hull while significantly increasing the draft of the vessel thereby limiting area of operation. U.S. Pat. No. 6,045,422, issued to Widmann, discloses a complex exhaust processing system for a boat including an exhaust chamber having an exhaust opening in the rear bottom thereof, and a wedge plate pivotally mounted at the forward end of the opening, with controls provided to selectively pivot the wedge to thereby change the negative pressure in the exhaust chamber. That system, however, appears overly complex and has not realized widespread commercial success.

Accordingly, there exists a need for an improved system for discharging marine exhaust at a submerged location below the water line.

BRIEF SUMMARY OF THE INVENTION

The present invention overcomes limitations present in the art by providing an improved marine exhaust system adapted for discharging marine exhaust below the water line through at least one streamlined conformal discharge fitting attached to the vessel hull. Each discharge fitting comprises a low profile body attached to the vessel hull in relation with an exhaust discharge conduit terminating in a thru-hull opening so as to discharge marine exhaust into the discharge fitting body. The discharge fitting preferably includes a forward end and an aft end connecting a main discharge fitting body disposed in spaced relation with the underside of the vessel hull. The discharge fitting body defines an exhaust outlet disposed on outboard side thereof so as to allow exhaust gas to exit in an outward and aft flow such that corrosive exhaust gas does not flow over the vessel propeller(s). Forward and aft baffles are disposed within the discharge fitting body to direct and re-direct exhaust gas flow. By maintaining a streamlined and low-profile/conformal shape, reduction in overall hull hydrodynamics due to increased drag is minimized.

Accordingly, it is an object of the present invention to provide an improved submerged exhaust system for marine vessels.

Another object of the present invention is to provide such a system wherein a streamlined exhaust fitting that substantially conforms to the bottom surface of the vessel hull and functions to distribute exhaust gas in an aft and outboard direction.

In accordance with these and other objects, which will become apparent hereinafter, the instant invention will now be described with particular reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 illustrates a hydrodynamic submerged exhaust discharge fitting in accordance with the present invention affixed to a marine vessel;

FIG. 2 is a schematic sectional rear view illustration of a marine vessel having submerged exhaust discharge fittings in accordance with the present invention;

FIG. 3 is a partial starboard side view of a marine vessel having a submerged exhaust discharge fitting in accordance with the present invention;

FIG. 4 is a partial bottom hull view of a submerged exhaust discharge fitting affixed in operative relation with a thru-hull exhaust outlet in accordance with the present invention illustrating water flow streamlines and exhaust gas flow;

FIG. 5 is a partial side outboard looking inboard view of a sectioned vessel hull having a submerged exhaust discharge fitting affixed thereto in accordance with the present invention;

FIG. 6 is a bottom view of a submerged discharge fitting in accordance with the present invention; and

FIG. 7 is a top view thereof.

DETAILED DESCRIPTION OF THE INVENTION

With reference now to the drawings, FIGS. 1-7 depict a preferred embodiment of a submerged exhaust gas discharge fitting, generally referenced as 10, in accordance with the present invention. FIGS. 1-5 illustrate discharge fitting(s) 10 in operative relation on a marine vessel. Discharge fitting 10 provides a generally streamlined hydrodynamic hull attachment structure that projects from the under surface of the vessel hull and is in fluid communication with an thru-hull exhaust gas discharge penetration, referenced as 100, for discharging marine exhaust below the water line. Discharge fitting 10 comprises a generally low profile, specially configured and streamlined discharge fitting attached to the bottom surface of a vessel hull so as to substantially conform thereto. Discharge fitting 10 includes a low profile, generally conformal structure attached to the vessel hull in relation with an exhaust discharge conduit terminating in a thru-hull opening such that exhaust gas is discharged into the discharge fitting body within an exhaust gas diffuser chamber 11. Discharge fitting 10 preferably includes a convexly contoured (when viewed from below) body or structure 12 with substantial central portions thereof in spaced relation with the vessel hull so as to define an exhaust gas diffuser chamber 11. Discharge fitting body 12 terminates in a fore/forward end 14 an aft/rearward end 16 and an inboard side edge 18 connecting the forward and aft ends. Forward end 14, aft end 16, and inboard side edge 18 are all shaped and contoured for generally fluid tight, substantially flush engagement with the bottom of the vessel hull whereas the remainder of body 12 is generally in spaced relation with the bottom of the hull as illustrated in FIG. 5 such that the discharge fitting 12 appears (when viewed from the centerline looking outboard) as a hydrodynamic streamlined bubble projecting downward from the bottom of the hull. Discharge fitting body 12 further defines an outboard edge 20, which includes an aft end terminating in contact with the hull, a mid-portion in spaced relation with the hull, and a fore end terminating in contact with the hull in proximity to forward end 14. Outboard edge 20 is recessed inwardly relative to the forward end 14 (when viewed from below) so as to define a cutaway portion as illustrated in FIGS. 4, 6 and 7. This structure functions as an exhaust gas outlet to allow exhaust gas to escape from gas diffuser chamber 11 in a generally outboard and aft direction such that corrosive exhaust gas does not flow over the vessel propeller(s).

Discharge fitting body 12 further includes contoured forward and aft baffles, referenced as 22 and 24 respectively, which function to define the fore and aft ends of chamber 11 thereby restricting gas flow within the general mid-portion of body 12. In a preferred embodiment forward baffle 22 comprises an arc-shaped wall extending laterally across fitting body 12 from inboard to outboard sides thereof in proximity to fore end 14. Baffle 22 has an upper end in conforming contact with the bottom of the hull and a lower end conformingly affixed to main body 12. Baffle 22 is preferably disposed to form a partition wall that is concave when viewed from exhaust gas diffuser chamber 11 as illustrated in FIG. 6. Aft baffle 24 comprises a curved, generally L-shaped wall that includes a first forwardly curved end 24A terminating at inboard edge 18, and an opposing second rearwardly curved end 24B that projects along outboard edge 20 to form a wall or partition terminating at the aft end of fitting body 12 defining the outboard cutaway portion as best seen in FIG. 6. Baffle 24 has an upper end in conforming contact with the bottom of the hull and a lower end conformingly affixed to main body 12. Baffle 24 is preferably disposed to form a partition wall to prevent exhaust gas from entering the aft portion of main body 12. Baffles 22 and 24 define the fore and aft ends of gas diffuser chamber 11, and side edge 18 defines the inboard terminus of gas diffuser chamber 11. As best seen in FIG. 2, discharge fitting body 12 is preferably positioned relative to an exhaust discharge, referenced as 100, such that exhaust gas is discharged at the forward end of diffuser chamber 11.

As illustrated in FIG. 4, water flows over and around discharge fitting 12 when the vessel is underway while exhaust gas exits thru-hull fitting 100. In a preferred embodiment thru-hull fitting 100 is generally circular as illustrated. In an alternate embodiment, thru-hull penetration 100 is elongated or oval having the maximum dimension running generally from foe to aft. Once discharged, exhaust gas in confined within diffuser chamber 11 by fore and aft baffles 22 and 24, edge 18, and the upper surface of body 12 disposed therebetween. The acceleration of water over and around the hydrodynamic fitting 10 results in reduced water pressure thereby providing a pressure environment to allow for the escape of exhaust gas. The exhaust gas thus is directed to exit fitting 10 by flowing in an outboard and/or aft direction as illustrated in FIG. 4. In a preferred embodiment, fitting 10 is located in proximity to the hull chine as illustrated in FIG. 4.

Discharge fitting body 12 is preferably fabricated from a fiberglass, carbon fiber, composite material, or any other corrosion resistant material. As should be apparent, the size, shape, and dimensional parameters of discharge fitting body 12 may be altered to suit the particular vessel hull, engine size, or other design considerations. In a typical dual exhaust installation, a pair of mirror image discharge fitting bodies may be used to provide hydrodynamically equivalent drag characteristics. A further significant advantage realized by streamlined shape and position of the installed exhaust discharge discharge fittings is a resultant upward lift that is proportional to vessel speed so as to improve the vessel's trim and planning characteristics. Discharge fitting 10 may further include generally L-shaped channels that run in an outboard direction from fitting body 12 in proximity to diffuser chamber 11 along the bottom of the hull and up the side of the hull to provide a conduit to atmosphere. Such L-shaped channels function to provide a path to the surface of relatively low water pressure.

The instant invention has been shown and described herein in what is considered to be the most practical and preferred embodiment. It is recognized, however, that departures may be made therefrom within the scope of the invention and that obvious modifications will occur to a person skilled in the art. 

1. An exhaust discharge fitting for use with a marine vessel, said vessel having a hull with a bottom that is at least partially submerged below the water line when the vessel is buoyantly disposed within a body of water and an exhaust system configured to discharge exhaust below the water line via a thru-hull opening, said hull bottom sloping from the centerline upward and laterally outward in starboard and port directions reaching the hull chine wherein the bottom and sides of the hull meet, said hull terminating forwardly at the bow and rearwardly at the stern, said exhaust discharge fitting comprising: an exhaust discharge structure attached to the bottom of the vessel hull; said structure including a mid-portion disposed between fore and aft end portions and inboard and outboard side edges; said mid-portion in spaced relation with the vessel hull so as to define a gas diffuser chamber; said structure attached to the bottom of the vessel hull in relation to the thru-hull opening such that exhaust gas exiting the thru-hull opening flows into said gas diffuser chamber; said fore end potion tapering from said mid-potion toward the hull and terminating at a peripheral edge in fluid tight engagement with the hull; said mid-potion tapering toward said hull in an inboard direction and terminating at an inboard side edge in fluid tight engagement with the hull; said aft end potion tapering from said mid-portion toward the hull and terminating at a peripheral edge in fluid tight engagement with the hull; said outboard side edge having a portion thereof in spaced relation with the hull and recessed inwardly relative to said fore end portion to define an exhaust gas outlet to allow exhaust gas to escape from said gas diffuser chamber in a generally outboard and aft direction.
 2. An exhaust discharge fitting for use with a marine vessel according to claim 1, further including a forward baffle extending laterally across said structure from inboard to outboard sides thereof in proximity to fore end, said forward baffle having an upper end in conforming contact with the bottom of the hull and a lower end conformingly affixed to main body.
 3. An exhaust discharge fitting for use with a marine vessel according to claim 1, further including an aft baffle extending laterally across said structure from inboard to outboard sides thereof in proximity to aft end, said aft baffle having an upper end in conforming contact with the bottom of the hull and a lower end conformingly affixed to main body.
 4. A submerged exhaust discharge fitting for use with a marine vessel, said vessel having a hull with a bottom that is at least partially submerged below the water line when the vessel is buoyantly disposed within a body of water and an exhaust system configured to discharge exhaust below the water line via a thru-hull opening, said hull bottom sloping from the centerline upward and laterally outward in starboard and port directions reaching the hull chine wherein the bottom and sides of the hull meet, said hull terminating forwardly at the bow and rearwardly at the stern, said exhaust discharge fitting comprising: a hydrodynamic exhaust discharge fitting convexly projecting from the bottom of the vessel hull; said structure including a mid-portion disposed between fore and aft end portions and inboard and outboard side edges; said mid-portion in spaced relation with the vessel hull so as to define a gas diffuser chamber; said structure attached to the bottom of the vessel hull in relation to the thru-hull opening such that exhaust gas exiting the thru-hull opening flows into said gas diffuser chamber; said fore end potion tapering from said mid-potion toward the hull and terminating at a peripheral edge in substantially flush fluid tight engagement with the hull; said mid-potion tapering toward said hull in an inboard direction and terminating at an inboard side edge in substantially flush fluid tight engagement with the hull; said aft end potion tapering from said mid-portion toward the hull and terminating at a peripheral edge in substantially flush fluid tight engagement with the hull; said outboard side edge having a portion thereof in spaced relation with the hull and recessed inwardly relative to said fore end portion to define an exhaust gas outlet to allow exhaust gas to escape from said gas diffuser chamber in a generally outboard and aft direction.
 5. An exhaust discharge fitting for use with a marine vessel according to claim 4, further including a forward baffle extending laterally across said structure from inboard to outboard sides thereof in proximity to fore end, said baffle having an upper end in conforming contact with the bottom of the hull and a lower end conformingly affixed to main body.
 6. An exhaust discharge fitting for use with a marine vessel according to claim 4, further including an aft baffle extending laterally across said structure from inboard to outboard sides thereof in proximity to aft end, and further extending along said outboard side edge, said aft baffle having an upper end in conforming contact with the bottom of the hull and a lower end conformingly affixed to main body. 